The 1980s and 1990s was the era of the great dispersal. Forty-three million people moved every year, and basically they moved outward -- from inner-ring suburbs to far-flung exurbs on the metro fringe. For example, the population of metropolitan Pittsburgh declined by 8 percent in those years, but the developed land area of the Pittsburgh area sprawled outward by 43 percent.

What will be the dominant domestic migration pattern of this economic downturn? Density is back in vogue and retiring Boomers will strain the ability of enterprise to cobble together a critical mass of brains. But instead of a big move back to the city, we might see the transformation of the bedroom community into a place where people also work and play.

The more perplexing mystery is figuring out where the population will relocate. Recent boomtown such as Austin should continue to draw talent, but the aging infrastructure of the Rust Belt is in much better position to benefit from the density trend. Chattanooga, Pittsburgh, Columbus, and Indianapolis all look to be winners in this go-round.